On March 12, the U.S. ambassador in the USSR, W. Averell Harriman, notified Vyacheslav Molotov of the possibility of Wolff's arrival in Lugano to conduct negotiations on the German Forces surrender in Italy.

On the same day, Molotov replied that the Soviet government would not object to negotiations between American and British officers and Wolff, provided that representatives of Soviet Military Command could also take part in them. However, on March 16 the Soviet side was informed that its representatives would not be allowed to take part in negotiations with Wolff in any case.

On March 22 Molotov, in his letter to the American ambassador, wrote that "for two weeks, in Bern, behind the back of the Soviet Union, negotiations between representatives of the German Military Command on one side and representatives of American and British Command on the other side are conducted. The Soviet government considers this absolutely inadmissible." This led to Roosevelt's letter to Stalin on March 25 and Stalin's reply on March 29. The actual surrender in Italy was signed on April 29, 1945 agreeing to a cessation of hostilities on 2 May.

Operation Crossword was depicted in the Soviet film Seventeen Moments of Spring, named "Operation Sunrise Crossword" in the film.

Meanwhile, Wolff's plan came to the attention of Adolf Hitler and Reichsführer-SS Heinrich Himmler both of whom, surprisingly, gave Wolff permission to continue his dialogue with the Allies and stall for time. On 29 April 1945, German emissaries signed the instrument of surrender at Allied headquarters in Caserta (in the presence of a Soviet delegation) with effect from noon on 2 May 1945. World War II in Italy thus ended six days earlier than in the rest of Europe. On 13 May 1945, Wolff was taken into captivity when U.S. troops of the 88th Infantry Division arrested him at his private villa in Bolzano.